Chemicals and techniques for effectively killing pathogenic microorganisms are useful in the fields of human and veterinary medicine. Application of high heat and pressure in an autoclave is one technique to inactivate many pathogenic microorganisms. Various chemicals such as bleach, hydrogen peroxide, peracetic acid, and glutaraldehyde may be used to kill pathogenic microorganism. The difficulty of inactivating microorganisms varies with the organism. Disinfection is generally defined as including any process, chemical or physical, that destroys most pathogens but may not kill bacterial spores. Sterilization refers to methods and chemicals that destroy all viable forms of microbial life including bacterial spores. Both disinfection and sterilization generally refer to the destruction of microorganisms on non-living objects.
The difficult of inactivating microorganism can be ranked according to a scale of susceptibility. Generally, a chemical or process that kills microorganisms in a given susceptibility group will also kill microorganisms in easier-to-kill susceptibility groups. Table 1 below shows a scale of susceptibility with the more-difficult-to-kill microorganisms listed lower on the scale. Thus, if a disinfectant kills microorganisms in susceptibility group D such as M. tuberculosis that disinfectant will also kill microorganisms in susceptibility groups A-C.
TABLE IScale of SusceptibilityMicrobialSusceptibilityGroupMicroorganism (dried on carriers)ARetroviruses (AIDS), ortho and paramyxoviruses, herpesviruses, vaccinia, corona, and other enveloped viruses, gramnegative rods and some filamentous fungi, some gram positivecocci, human hepatitis B virusBStaphylococcus aureus, some diphasic and filamentous fungi,yeasts and algae, some gram negative rodsCAdenovirusDMycobacterium tuberculosis (BCG strain), rotaviruses,reoviruses, some mold ascosporesEPicornaviruses (polio, rhino), parvoviruses, hepatitis AFBacterial endospore (Bacillus, Clostridinium), viroidsGPrions (chronic infectious neuropathic agents, slow viruses)
Human skin is frequently colonized with a flora that varies depending on the location on the body and the setting. Normal human skin flora may include several types of bacteria such as gram-positive cocci, gram-positive-rods, and gram-negative bacteria. Most of these types of bacterial, other than gram-positive rods such as Bacillus and Clostridinium, are categorized in microbial susceptibility groups A and B above. Thus, any solution which kills microorganisms in groups B, or any of the more-difficult-to-kill groups, would be effective against most bacterial that normally colonizes human skin.
Skin and soft tissue infections are among the most common type of infections afflicting humans. Skin and soft tissue infections may lead to serious local and systemic complications. One of the common causes of skin and soft tissue infections is the occurrence of secondary bacterial infection that complicates treatment of skin lesions. Skin lesions that can also be secondarily infected with bacteria and fungi. Thus, a skin or soft tissue infection may actually be a result of the interaction of multiple microorganisms. Examples of this type of skin lesion include, but are not limited to, skin lesions caused by scabies, psoriasis, poison ivy, atopic dermatitis, eczema herpeticum, or kerion. Oral or systemic antibiotics may be effective at treating bacteria. However, there is a delay while a systemic antibiotic moves through a patient's body to the site of infection. Additionally, antibiotics are not effective for treating infections caused by microorganisms other than bacteria. Thus, there is a need for treatment techniques that can address infections caused by multiple microorganisms.
Many of the techniques and chemicals used for disinfection and sterilization are not suitable for application to living tissue or skin. The features of such techniques which make them effective at killing pathogenic microorganisms also cause harm or death to healthy living tissue. Antimicrobial substances that are suitable for application on the skin or tissue of humans and animals are referred to as antiseptics. However, because of the design for use on living tissue, many antiseptics are less effective at killing pathogenic microorganisms than disinfectants or sterilants. Thus, there is a need for antiseptics with improved efficacy.